June
23, 2005 — Forecasters at the NOAA
Storm Prediction Center in Norman, Okla., now have additional tools
to more accurately predict the occurrence of cloud-to-ground (CG) lightning
flashes within thunderstorms. The lightning climatology and lightning
prediction system helps meteorologists determine areas where these lightning
flashes could threaten lives and property and start wildfires. (Click
NOAA image for larger view of the NOAA Storm Prediction Center’s
fire weather outlook for the United States as of June 23, 2005. Please
credit “NOAA.”)

Lightning
that strikes the ground kills approximately 67 people each year and
leaves hundreds of survivors with debilitating health effects. Each
year, NOAA designates the last full week of June as Lightning
Awareness Week to promote safe outdoor and indoor activities before,
during and after lightning begins flashing.

CG lightning
also causes many of the largest forest fires in the United States, especially
in the West. These flashes are associated with dry thunderstorms that
produce lightning but little rainfall. During the disastrous wildfire
season of 2000 in the Northern Rockies, nearly all of the wildfires
were started by lightning, according to the National Interagency Fire
Center. Better prediction of thunderstorms, days in advance, will allow
for better positioning of resources, including firefighters and equipment,
on the ground to fight lightning-sparked fires while they are still
small.

CG lightning
was the focus of an eight-year climatology study for the period from
1995 to 2002 completed by Phillip Bothwell, NOAA Storm Prediction Center
senior development meteorologist. While most researchers develop climatologies
over long periods of time (monthly or yearly), Bothwell broke up his
observations into five-day blocks of time in an effort to see if more
detailed patterns emerged from shorter time periods. He also derived
the climatologies for every three hours to see how lightning patterns
changed during the day.

"A
climatology serves as one type of objective guidance in predicting where
lightning is more likely to occur," said Bothwell. "It serves
as a predictor by giving forecasters an accurate sense of when and where
storms tend to form so they can better advise people in that area."

Bothwell
said one of the driving forces behind the climatology comes from his
interest in extreme lightning events with a large number of flashes.
With this lightning prediction system, forecasters can look at the probability
of one or more lightning flashes in a 40 x 40 km grid box, equivalent
to an average-sized county. They can also examine the probability of
more extreme occurrences, such as 100 or more CG flashes in a grid box.
These large flash events can be very dangerous and destructive to many
types of electrical systems. In the United States, 20 to 25 million
cloud-to-ground lightning flashes occur each year and many of these
CG flashes come from extreme lightning events.

"These
storms with large numbers of lightning flashes are dangerous and destructive
by themselves," Bothwell said. "In addition, they are often
associated with severe weather such as tornadoes, hail, wind and flooding."

Forecasters can
use the lightning climatology information, along with other observed
and model data, to better pinpoint when and where lightning will occur.
The NOAA Storm Prediction Center is currently producing experimental
lightning forecasts extending three days into the future.

The NOAA
Storm Prediction Center issues forecasts and watches for severe thunderstorms
and tornadoes over the contiguous United States. SPC also monitors fire
weather conditions, heavy rain and heavy snow events across the U.S.
and issues specific national products for those hazards. Part of the
NOAA National Weather Service's National
Centers for Environmental Prediction, SPC meteorologists are on
duty 24 hours a day, seven days a week. Established in Washington, D.C.,
in 1952, the center moved to Kansas City in 1954 and then to Norman
in 1997.

NOAA, an
agency of the U.S. Department of
Commerce, is dedicated to enhancing economic security and national
safety through the prediction and research of weather and climate-related
events and providing environmental stewardship of the nation's coastal
and marine resources.